A known hydrogel particle containing an oil component is a hydrogel particle formed by the continuous phase portion of non-crosslinked hydrogel and the disperse phase portions containing an oil component (see, for example, Patent Document 1). The hydrogel particle is characterized in that, when used in a cosmetic product, or the like, the particle can be smoothly crushed by fingers at the time of application over the human skin, or the like. Further, it exhibits excellent spreadability with no residue and excellent crushability.
Although a hydrogel particle containing a pigment as a colorant in the disperse phase portions has been known, there has not been a hydrogel particle containing zinc oxide particles which have UV-shielding property in the disperse phase portions.
Zinc oxide is naturally soluble in water in a small amount. Such solubility causes various disadvantages in designing cosmetic products. For example, in the case of a conventional sunscreen cosmetic product containing ultrafine powder of zinc oxide, it is difficult to increase the water content to 50 mass % or more. Thus, most of the emulsified products are water-in-oil (W/O) products. Meanwhile, ultrafine powder of zinc oxide can react with other ingredients, such as a variety of oils, perfumes, colorants, organic UV absorbers, water-soluble polymer, etc., to cause an increase or decrease in viscosity of the cosmetic product, to produce a stench, or to cause discoloration. Because of such problems, the use of ultrafine powder of zinc oxide in cosmetic products is restricted with limited applicability.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-159838 (Japanese Patent No. 3483543)